Abstract: Hydrogel has been widely used in the research of bionic articular cartilage due to their similarity in structure and functional 
properties to natural articular cartilage. In this research, polyvinyl alcohol and betaine monomer were used as raw materials to prepare a high-strength double-network hydrogel by a combination of ultraviolet (UV) irradiation and freeze–thaw 
methods. The structure of samples was characterized by Fourier transform infrared spectroscopy and X-ray diff raction, 
and the morphology of the samples was characterized by scanning electron microscope and three-dimensional white light 
interferometer. In addition, we also studied the swelling ratio, water content, mechanical properties and tribological properties of the samples. We found that the addition of betaine monomer and the UV irradiation time had a positive eff ect on the 
mechanical properties and tribological properties of the samples.

Key words: Polyvinyl alcohol, Double-network hydrogel, Ultraviolet irradiation, Low friction, High strength